Method for charging individual capsules with a compressed gas



y 1949. s. s. M CLOY 2,469,975

IETHOD FOR CHARGING INDIVIDUAL CAPSULES WITH A COMPRESSED GAS F1196 NOV.'7, 1946 HELD III 24 11 2 24 zz f 27 3L\ i- 24 ll 24 22 ll FIG. 6.

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Lg ATTRNEY Patented May 10, 1949 METHOD FOR CHARGING INDIVIDUAL CAPSULESWITH A COMPRESSED GAS Graham S. McCloy, Springfield, Mass., assignmtoWestinghouse Electric Corporation, East Pittsburgh, Pa., a corporationof Pennsylvania Application November 7, 1946, Serial No. 708,392

1 Claim. (Cl. 226-20) This invention relates to a method for chargingindividual capsules with a compressed gas. The invention further relatesto the structure of the capsule formed by my new method.

The invention is particularly applicable to capsules of the type whereinthe contents thereof are adapted to be discharged into the atmospherewhile held by the user, the capsule being normally hermetically sealedand having a frangible portion to be broken oil by the user .to permitdischarge of the contents.

In such capsules it is often desirable that the flow from the capsule becontrolled at a predetermined rate in order that the discharged fluidshall have certain prescribed characteristics. This is particularly truewhen the capsule contains compressed gas in liquid form in which aredissolved certain insecticidal materials. In the latter case, it isdesirable that the mixture form an aerosol or suspension of minuteparticles of the relatively non-volatile insecticide which remainssuspended in the air for a considerable time after its discharge. Tothis end, it is desirable that the rate of discharge be controlled quiteaccurately.

Heretoiore, in preparing such capsules it has been the practice to firstform the individual capsu1e and then charge it by a rather complicatedmachine which automatically charges and also seals the capsule.

An object of the present invention is to provide a charging and sealingmethod and means wherein the compressed gas and any substance dissolvedtherein is first admitted to a relatively long, continuous tube sealedat one end, after which individual capsules of predeterminedcharacteristics are formed and sealed from the charged tube.

A further object is to provide a capsule so formed which has the desiredconstruction to permit proper aerosolformation if .the nature of itscontents so requires.

The foregoing and other objects are eflected by the invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawings, formin a part of this application, inwhich:

Fig. 1 is a plan view of a capsule formed according to my invention;

Fig. 2 is a side elevation of the capsule of Fig.

Fig. 3 is a section taken on line III-III of Fig. 1 and showing thedischarge orifice;

Fig. 4 is an end view of the capsule;

Fig. 5 is a schematic representation in plan 2 view of the successivesteps in the formation of the capsules from a continuous tube; and

Fig. 6 is a side elevation schematically showing the charging system.

According .to my invention and referring to Fig. 6, a continuous tube [0having a considerable length, on the order of several hundred feet, iscoiled about a hollow axle H. The tubing material will, of course, bedetermined by the nature of its charge, in that it should be strongenough to resist rupture under abnormal pressure conditions and itshould also be noncorrosive with respect to its contents. In practice, Ihave used flexible steel tubing of approximately 0.500 inch outerdiameter and 0.460 inch inner diameter where the contents comprisedapproximately per cent of dichloro-difiuoromethane as a propellant foran insecticide comprising a small per cent of pyrethrum extract with asuitable mutual solvent.

Before charging, the outer end of the tube is hermetically-sealed, asindicated at II. The inner end of the tube is connected by a suitablesealed coupling l3 to the rotatable shaft H and the end of that shaft isconnected by a suitable sealed coupling M to a conduit I5 which is inturn connected to a closed tank or pressure vessel l8 containing thecharging mixture. Heating means, here indicated as a pipe coil ll,should be provided to maintain the temperature of the tank i6 at apredetermined degree over that of the tubing ID, to ensure fluid flowfrom the tank to the tube. The fluid-tight coupling it between thestationary conduit 15 and the hollow rotating shaft is not described indetail as such connections are well-known in the art.

In describing the steps of forming the individual capsule, let it beassumed that the tube III in Fig. 6 is fully charged with a suitablecompressed gas, with or without added substances. Now, referring to Fig.5, a suitable tool 20 simultaneously presses a portion of the tube intogether, as indicated at If, and also scores the tube, as indicated at22, at the outer end of the pressed portion. Next the tube is contactedat the flattened portion by a welding machine 23, which forms two weldedportions 24 somewhat near the center of the flattened portion but spacedapart. These welds extend completely across the flattened portion andform two hermetic seals. Next the tube is contacted by a welding machine25 which forms one or more spot welds 26 adjacent the edges of theflattened portion between the scored portion 22 and the main body of thecapsule 21. Finally the flattened portion is contacted by a cutting tool28 between the two welded portions 24 so that the flattened portion isseparated at this point, resulting in the formation of the individualcapsule 30.

It should be noted that the spot welds 26 do not completely close thespace between the main body 21 of the capsule and the scored portion 22,but only serve to reduce the area of this space to provide a restrictedflow passage 3! (Fig. 3) from the body of the capsule to the atmospherewhen the end of the capsule is broken oil? at the scored portion 22.This weld may be of any type which does not completely close thefiattened portion at this point, and is of such a character as to leavea passage of suflicient area to provide the desired flow characteristicsas determined .by the nature of the material to be discharged. Theflattened portions 24a lying between the sealed ends 24 and the mainbody portion 21 ofier a safety feature in that they provide sectionswhich will expand under the influence of pressure of the contents due toany increase in temperature above that at which the capsule was charged.

It should also be noted that during the formation of the individualcapsules from the charged coil or tubing, any of the charge displaced bythe various steps is forced back into the storage tank is.

Inuse, the capsule of Fig. 1 is grasped in one hand and the end portion32 is flexed by the other until that portion is broken oil at the scoredportion 22, whereupon the contents are discharged through the orifice3|. For an effective aerosol formation, it is preferable that thecapsule be tilted downwardly toward the frangible portion 32 duringdischarge.

The capsule, of course, need not contain insecticidal material, but maybe used for the discharge of many substances including perfumes,deodorants, disinfectants, repellents or any material which may bedischarged from a closed container by a compressed gas.

In the manufacturing steps, it is understood that the charged tubing maymove continuously to aligned stamping and welding machines, or may bemoved intermittently as the individual capsules are formed at a singlestation by a machine which itself moves to perform the successive steps.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications without departing from the spiritthereof.

WhatIclaim is:

The method of charging and forming individual capsules from a continuoustube, which method comprises sealing one end of the tube, supplying afluid under pressure to the other end of the tube to completely fill thetube with the charging mixture, flattening a portion of the tube apredetermined distance from the end thereof, scoring the flattenedportion adjacent the end thereof, welding the flattened portion beyondthe scored portion to form an hermetic seal, partially welding theflattened portion between the body of the tube and the scored portion soas to leave a restricted passageway, and severing the formed capsulebeyond the hermeticallysealed welded portion.

GRAHAM S. MCCLOY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

